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REVIEW OF LITERATURE
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\..11 0 o--
!Rcwiew Of Literature
"Pollution is nothing but the resources we are not harvesting. We allow them to
disperse because we've been ignorant of their value. ··
Buckminster Fuller
Soil is the complex mixture of the decomposed organic material and eroded rock
tex-tures on of earth's surfaces that support plants they underlie the foundation of
houses and factories and determine whether the foundations are adequate. They
are having miscellaneous properties with the integrated effects of climate and
living matter acting upon parent material, as conditioned by relief, over period of
time (USDA, 1951). People are dependent on soil, and conversely, good soil is
dependent on people and the uses they make of the land soil also have other
meaning of human kind. Soil is used to absorb wastes from sewage systems,
wastes from other municipal, industrial, and animal sources. Unfortunately
misused and unprotected soil can be deposited in municipal reservoirs, impairing
water quality and shortening the usefulness of the reservoir (Brady, 2000).
Modern society discharges many waste products and chemicals in the water,
which enter the soil, and affects all forms of life. The release of solid waste to the
environment may lead to contamination of water supplies, endemic disease,
offensive smell and eutrophication of waterways. In addition to these solid waste
is also known for its potentially elevated organic pollutants (e.g. phenols,
polychlorinated biphenyls) (Lottermoser, 1995).
Phosphorus in Soil and Plants
a) Literature of abroad
P is an essential nutrient for plant growth, required in relatively large quantities
by plants, and considered relatively immobile in soils. Normally P becomes
"sorbed" on soil particles, and this makes P less available for plant uptake or
leaching. In time, as less soluble compounds are formed, P becomes less
available, and P adsorption sites subsequently may be regenerated. Several
investigations with waste products have indicated that, even though organic P
may be more mobile than inorganic P in the soil profile, the extent of P
movement is limited compared to the movement of N. (Miller et al 1976)
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~~Of Literature
reported that soluble P levels were higher immediately below hog manure
lagoons but decreased to background levels within 20 to 30 em.
Land application of organic wastes obtained from different sources (Municipal,
Industrial, or zoo technical) has two advantages: it avoids accumulation of wastes
in the environment and it provides organic mater and nutrients for soil. It is also
widely accepted that the nutrient content and organic matter content of any
wastes are its primary desirable properties relative to its utilization on land.
Because they are enriched in N and P, so supposed that they can increase crop
yield (Narwal et.al., 1983, National Research Council, 1996).
Kelling et a! in 1977 applied the liquid digested sludge at different rates in a
sandy loam soil and found that sludge applications resulted in immediate marked
increased in Bray's extractable P. However, the extractable P levels decreased
with time after sludge application, probably as a result of P fixation. Significant
amounts ofP remained available for at least 2 years at the higher treatment rates.
Soon et a! (1978) found significant increase in 0. 5M NaHC03 extractable P in
soils with increasing rates ofP addition of lime, Fe, and Al precipitated sludge.
Johnston (1981) on the Woburn Market Garden experiment and indicated that
sewage sludge applications from 1942 to 1967 resulted in increase in plant
available Pas measured by O.SM NaHC03 extraction.
A ling term experiment using corn was initiated on calcareous stripe mines spoil
to evaluate the effect of an-aerobically digested sewage sludge on spoil crop
system. They found that grain yields were significantly affected by sludge
application, but Stover yields were not affected. Concentrations ofN, P, K, Ca,
and Mg min corn tissue varied in response to sludge applications. Leaf and grain
P and grain K declined with higher rates of sludge application (Peitz et al 1982).
Gastring and Jarrell (1982) studied the plant availability of phosphorus and heavy
metals in three soils (acid, neutral and alkaline) amended with chemically treated
(Ah (S04)3, FeCh and Ca (OH)2 sewage sludge. They observed that bicarbonate
extractable P increased with the addition of sludge. However, no discernible
-22-
trends in P uptake by the Chard were observed for any of the fertilizer treatments
or application rate.
Inman et al. (1982) applied treatments of 0, 150, and 300 metric tons/ha (dry
weight basis) of fresh-composted sludge material to a Chester silt loam in
Maryland with no detrimental effects. In fact, the subsurface soil solution was
generally below 0.08flg/ml, and the compost-treated plots were equal to or lower
in soluble P than were samples taken from the control plots.
Robertson et al (1982) applied 0, 87, 174, 241, 288, and 355 metric tons/ha of dry
matter from liquid-digested sludges over a 6-year period. They noted that, even
though the amount ofP added to the soil was large, P did not move appreciably.
Most of the P remained in the top 90 em of the soil profile, and P accumulation
decreased with depth.
Wong (1985) in an. experiment found that trace metals content in the roots were
increased most by a combined application of NPK and digested sewage sludge.
NPK alone had an intermediate effect and digested sewage sludge alone had least
effects on these contents.
McCoy et al in 1986 carried out a greenhouse and field studies to compare the
effectiveness of Blue plain sewage sludge compost, Parkway sewage sludge
compost, and triple super phosphate (TSP) as source ofP for com. They noticed
that application of TSP stimulated com growth much more than applications of
containing equivalent total P.
Seeda et al (1990) in an experiment found that acid sludge amendment in sandy
soil increased the P uptake by V. sativa up to 1. 0% of sludge; after it decreased
and at more than the 3.0% amendment plants died.
Chrenykh (1991) in a pot culture experiment studied the effects ofZn, Pb and Cd
on major and trace elements by barley and Vicia sativai. They reported that
increase of soil Cd to 5ppm, Zn to 250 ppm and Pb to 125 ppm didn't alter the
plant mineral uptake, but higher heavy metal concentration disrupted the mineral
-23-
?(eview 0{ Literature
uptake and translocation. Reduction in uptake of P, Ca, mg, Fe and Cu were
found in both plants but it was more pronounced in V. sativa than the barley.
The sewage sludge can be used. as a fertilizer source to maintain crop
productivity. It can improve the physical properties of soils (Sirisukhodom, 1998)
by increasing soil porosity, and the stability of soil aggregation (Pagliai et al.,
1981 ). Sludge application can increase the complexation and adsorption capacity
of soil, enhancing the ability of soil to retain metals (Karapanagiotis et al., 1991).
Zhou et al (1994) analyzed undigested sewage sludge and showed that it
contained high level of organic matter, N and P. When they added sludge to
sandy loamy soil, sewage derived N and P were readily taken up by cauliflower
and cabbage and yields were increased.
Frossard et al in 1996 when assessed the quantity of P that can be released from
sludge and taken up by English ryegrass grown on sludge amended soil found
that sludge increased soil available P and contribute to the P nutrition of the test
crop. The utilization P derived from the sludge was systematically lower than the
utilization ofP derived from a water soluble fertilizer.
Mohammad and Battikhi (1997) studied the effect of sewage on some soil
properties and barley plant growth in field study. They found that incorporation
of sewage sludge significantly decreased the pH of soil and increased the EC and
organic matter. Sludge application increased extractable P in soil and P content in
straw and grains ofbarley.
A greenhouse study (Angela et al 2003) was conducted to asses P avoid
availability from feces with low, medium, and high P concentrations from a dairy
feeding study, whole (unfractionated) manure, fiber manure from a liquid solid
separator, biosolids from a municipal waste treatment facility, and calcium
phosphate (CaHP04). This observation emphasizes the importance of growing
media characteristics in greenhouse experiments to assess P availability. These
results suggest that soluble P sorption by soil, available P contribution from soil,
and mineralization of organic P from the P source treatments masked initial
differences in P availability among these P sources.
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~Of Literature
Connor et al in 2004 conducted a greenhouse studies with a common pasture
grass grown in two P-deficient soils amended with 12 biosolids and a commercial
fertilizer (triple superphosphate, TSP) to quantify P uptake and to assess the
relative phytoavailabilities of the P sources. They have classified bios lids on the
basis of P availability in 12 classes. The entire biosolid has more P availability
but two of them have more P than fertilizer.
Bar-Tal (2004) conducted a green house study to determine the loading rate of
compost to land. They found that total dry matter (DM), grain production, and the
amount ofN, P, and K taken up by plants increased with increasing compost rate.
b) Indian Literature
Due to rapid industrial development during the last two decades in India, the
disposal of industrial effluents and solid waste has become a serious problem.
The tannery and textile are two important industries in the country. The
application of these industrial effluents to land has started in recent years as an
alternative means of treatment and disposal. This supplies not only water (a
source of irrigation) but also manorial ingredients and plant nutrients like N, P,
K, S and Ca etc. If these effiuents are treated properly and reused judiciously in
agriculture, they may serve as a source of irrigation and source of plant nutrients.
In a pot culture studies (Lal et al, 1996) with acid Alfisol (pH 4.9) amended with
fly ash, highest dry matter yield of soybean was obtained in treatment receiving
16% (w/w) fly ash. A drastic reduction in plant growth was observed at higher
levels. Fly ash application increased pH, organic carbon as well as available P
and K status of the acid soil.
Giri and Bhattacharyya (1999) analyzed the solid wastes generated in Wazirpur
Industrial Area of Delhi, dumped on the road sides of three blocks (A, B, C).
Twenty-four representative samples were collected from three different blocks
for the analysis of 12 physico-chemical parameters to characterize these solid
wastes. The results revealed that the generated wastes were acidic (pH-3 .48) in
nature with electrical conductance (EC) 75 mS/cm, moisture content 35.67%,
water holding capacity 52.85%, organic carbon 2.518%, available N 216 ppm,
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~eview· Of Literature
total N 0.292%, available P 42 ppm, total P 0.182%, C/N ratio 9.33. The total
concentration of nutrient elements were K 0.230%, Mg 0.420%, Ca 1.900%, Na
1.510%, Fe 12.300%, Zn .040%, Cu 0.210% and Mn 1.15%. The total
concentrations oftoxic metals were Cr 9643 ppm, Cd 83 ppm and Pb 100 ppm.
A field experiment was conducted by the application of industrial wastes like,
fly-ash, paper sludge, and rice husk ash, which improved the physico-chemical
properties of soil in terms of decrease in bulk density, increase in pH, organic
carbon and available nutrients like, N, P, K, Ca, Mg, Cu and Co (Mittra et. al,
2000). This study indicates that ample scope of using industrial wastes on
agricultural land. As it can help to overcome the problem of environmental
pollution at industrial sites while maintaining ecological balances.
Mishra and Das (2000) in a pot culture study found that available P in
Farmyard Manure mixed soil increased up to 15th day but after that it decreased
up to 45th day and then again increased up to their study period that is up to 75th
day. They also found that maize yield was high in Farmyard Manure mixed
soil, having more organic matter in compared to control soil. On the basis of
this study they concluded that organic matter helps in P amount in maize plant
and soil.
When wheat was grown on contaminated soil Zahangren et al (2002) found that
soil pH and available P affect the uptake of Cd in grain. P content of grains and
P uptake is linearly related to concentration in soil.
Heavy Metals in Soil and Plants
a) Literature of abroad
Heavy metals usually refer to elements having densities greater than 5. Metals
(Zn B, Cu, Fe, Mn and Mo), which are required in small quantity to plants, are
termed as micronutrients. But sometimes trace elements are synonymous for
heavy metal. There are several sources of trace element in environment both
natural and man-made: soil parent material, sewage sludge, fertilizer, liming
materials, animal wastes, irrigation water, fly-ash, metal smelting industries, auto
emissions and others. Some heavy metals are micronutrients, essential for plant
-26-
growth and therefore are beneficial to the crop (e.g., copper and zinc), however,
in excess they can reduce growth or can be toxic to plants. Other heavy metals are
not essential for plant or animal nutrition but are toxic to animals and humans
above defined levels (e.g., arsenic, cadmium, lead, and mercury). Heavy metals
are a concern because:
• they do not degrade over time,
• they are relatively immobile in the soil, and
• they accumulate in the plow layer of the soil.
Thus, the use of waste can be problematic because causes addition of harmful
components such as pathogenic organisms, chemical pollutants or excess inputs
of N and P (Vander Berg, 1993). A limiting factor to use waste on land is its
heavy metal content like Zn. Cr, Ni and Cd, which can produce phytotoxicity
(Webber, 1972; Saurbeck, 1985).
Numerous studies have been conducted to determine the effects of potentially
toxic metals in sewage sludge on crops, since the accumulation in plants poses a
potential health· hazard to plants, animals, and humans. Limited information is
available on the reactions of metals in municipal sewage sludge with soils, so
reactions between metals in sludges and soils are not completely understood.
Many researchers have reported that after municipal sewage sludge is
incorporated into soil, portions of the metals revert to non-extractable, less
available chemical forms (Beckett et al., 1979; Wollan and Beckett, 1979;
Lagerwerffet al., 1977; Silviera and Sommers, 1977; Dowdy and Larson, 1975).
On the one hand, with time, these ions form inorganic compounds or stable
organic complexes, which resemble the "native" soil forms of these metals
(Beckett et al., 1979; Wollan and Beckett, 1979; Lagerwerff et al., 1977;
Cunningham et al., 1975c). On the other hand, for example, some metals change
only slightly in chemical character after addition to soil. Chromium, which is
present as a colloidal precipitate in municipal sewage sludge, changed little in its
chemical form. It remained mostly insoluble after incorporation of sludge in soil
(Grove and Ellis, 1980).
-27-
~t:view 0{ Literature
In England, Patterson (1971), Chumbley (1971), and Webber (1972) observed
through greenhouse and field trails with sewage sludge-amended soils that Cu,
Ni, and Zn accumulated under certain conditions in soils to phytotoxic
concentrations. They also noted that, in general, Cu and Ni were 2 and 8 times
more phytotoxic, respectively than, Zn, which led them to propose the "zinc
equivalent" for assessing the phytotoxic, from these metals in soils.
Bingham et al. (1975) observed that spinach, soybeans, lettuce, and curlycress
were injured by soil Cd levels of 4 to 13 Jlg/g soil. These plants tend to
accumulate Cd in shoots; whereas, lower shoot accumulators like tomato and
cabbage could tolerate soil Cd levels of 170Jlg/g without injury.
Cunningham et al. ( 197 5) also conducted a green house experiment with soil
amended with sewage sludge enriched with various combinations of heavy
metals. Their treatments consisted of there concentrations each of Cr, Cu, Ni and
Zn added to a pH 6.8 soil cropping with com (Zea mays L.) and rye (Secuele
cereal L). Multiple regression analysis ofthe metal treatments showed a number
of metal combination reducing yields, with the Cu-Zn interaction accounting for
as much of the yields variation as any combinations expect the four way
interaction (Cr-Cu-Ni-Zn). They called attention to the complex nature of such
interactions occurring in ultimate experiments.
Dowdy and Larson (1975) mixed municipal sewage sludge into two
topographically associated soils with different pH levels of 5.9 and 7.9 (with free
carbonates). After incubating the sludge-soil samples for one growing year, the
researchers grew barley (Hordeum vulgare L.) to measure the quantities of plant
available potentially toxic metals. Incubation, sludge application rate, and soil pH
affected metal accumulation within the roots and tops of barley seedlings. As
sludge application rates increased, an increase in the removal of Cr, Ni, Zn, and
Pb occurred when barley was grown on the acid soil. However, there was no
change in the uptake of these metals when barley was grown on the high pH soil.
Thus, with different levels of soil pH, metals released by the decomposition of
sewage sludge either increased or decreased in availability for plant uptake.
-28-
The Council for Agricultural Science and Technology (CAST, 1976) classified
Cd, Cu, Mo, Ni, and Zn as potential hazards in land application of municipal
sewage sludges. These metals tend to accumulate in plants and cause either
reduced yields or health problems to animals or humans that ingest the plants.
Lagerwerff et al. ( 1977) reiterate that the formation or the strengthening of metal
complexes with higher soil pH levels and incubation affects their availability.
Kelling et al in 1977 in a field experiment studied the metal concentration in soil
and plant tissue resulting from of land application of liquid digested sewage
sludge. They found that addition of sludge increased the concentration of Cu, Zn,
Cd and Ni in the vegetative tissue but the addition had little affect on the metal
content of corn grain. Cr didn't accumulate in tissue or grain. In their study
concentration of metals were below the toxic level.
Ham and Dowdy (1978) determined the Cd and Cu concentrations in the aerial
portions of soybeans and reported that these two elements were primarily located
in the leaves, stems, and husks. In wheat, concentrations of trace elements in
plant parts followed a similar pattern with the concentration in roots > leaves >
stems > grain. Sims and Boswell, 1978 also found the same trend for Cd. Thus,
the potential hazard from metals is reduced if only the seed is harvested and used
as a food source. The specific amount of a trace element taken up by a plant
species is directly proportional to the amount of sludge-borne metals added and
the growth stage of the crop Lagerwerff et al, 1977 also reported the same thibg.
The concentrations of Cd, Cu, Mn, Ni, Pb, and Zn in the edible parts of lettuce
tops (Lactuca sativa L.) and onion bulbs (Allium cepa L.) were generally much
higher when the plants were grown on sludge-amended soils in the greenhouse
rather than when the plants were grown in the field (De Vries and Tiller, 1978).
Dowdy et al. (1978) reported that the concentration of Zn and Cu in bean leaf
tissue increased with amount of metals supplied to soil through additions of
sludge, until they reached a maximum concentration which did not respond to
further applications of metals.
-29-
Although plants can absorb large quantities of heavy metals. The roots generally
accumulate the most and often serves as storage sites preventing toxic dosages
from reaching the stem and grain was illustrated by Kirkham (1978) in an
experiment with chrysanthemum (Chrysanthenum morifolium Ramat.) roots
accumulated almost 10 times more Cd than the stem and the leaves when grown
in a culture solution supplemented with Cd.
pH near to 6.5 reduces the metal uptake by plants in sludge-amended soil.
Increases pH generally enhances the sorption of Cu, Zn and Cd by soils and
reduce plant uptake of Cd and Zn (Street et.al., 1978). Increasing pH generally
enhances the sorption of Cu, Zn, and Cd by soils (Cavallaro and McBride 1978;
Kuo and Baker 1980; Soon 1981;) and reduces plant uptake of Zn and Cd (John
et el 1972; Anderson and Neilson 1974; Street et al 1978).
Mitchell et al. (1978) evaluated uptake and phytotoxicity characteristic ofCd, Cu,
Ni, and Zn with a greenhouse experiment consisting of an acid soil and a
calcareous soil amended with 1% sewage sludge enriched with low to phytotoxic
concentrations ofthese metals added alone (separate experiment for each metal)
using lettuce (Lactuca sative L. var. Longifolia) and wheat (Triticum aestivum L.
Inia) as test crops. The order of toxicities by test plants was not the same for all
soil and crop species combinations but in general, Cd was the most toxic,
followed by Ni, cu, and Zn. A subsequent investigation on the interactive effects
of Cd, Cu, Ni and Zn when present tighter at low, intermediate, and high
phytotoxic concentrations.
Sewage sludge is the solid byproduct of domestic and I industrial waste, water/
treatment plant. Philadelphia has developed a system of composting and of land
application of sewage sludge on a basis for its sources (Lochar, 1979). Heavy
annual application of sludge on land can increase the organic matter and nitrogen
content ofthe soil (Sheaffer, 1979).
Crops grown on the sludge-treated soils, however, can contain higher
concentrations of accumulated metals than those grown on uncontaminated soils
(Carlton-Smith and Davis, 1983; Dowdy and Larson, 1975; Keefer et al.; 1986).
Many climatology, soils property and crop cultivars related factors can affect the
-30-
~Of Literature
ability of a land to absorb metal elements (change et al, 1987 and Corvey et al
(1987) reviewed interactions between these factors. Based on its concentrations
in the muniCipal sludges its chemistry in the soils and the ability of plants
accumulates it Cd is regarded as potentially the most hazardous metal element
when sludge are applied on land (Burai, 1980; Council for Agricultural Science
and Techonology 1980; Logan and Chaney 1983; Pahren et al; 1979; Ryan et ai
1982). Plant uptake may allow Cd to enter the human food chain.
Bowen (1979) estimated the general residence time of metals in the soil system to
be between 75 year to 380 year for Cd, and between lOOOyrs to 3000 yrs for Cu,
Pb, and Zn.
Gastring and Jarrell (1982) studied the plant availability of phosphorus and heavy
metals in three soils (acid, neutral and alkaline) amended with chemically treated
(Ah(S04)J, FeCb and Ca(OH)2 sewage sludge. They found that the increased
plant level of Zn, Mn and Cd appear to be the result of lower pH produced up on
the addition of Al-treated sludge. No significant difference in Fe, Ni and Pb
concentrations were found in plant tissue for any of the treatments or application
rates.
Mahler et al (1982) when Cd enriched sewage sludge applied to acid &
calcareous soils found that Cadmium additions to the soils generally decreased
Zn and Mn concentrations in saturation extracts in calcareous soils. These
decreases were reflected in reduced concentrations of Zn and Mn in leaves of the
test crops. The relationship between saturation-extract compositions of Cd, Zn •
and Mn and their plant compositions were found to be different for the acid as
compared with the calcareous soil groups.
Higgins (1984) in his study applied sewage sludge at rates ofO, 22.4 and 44.8 mg
of dry solids /hat. He found that Zinc and copper get accumulated in the soil
horizon; however no accumulation occl!rred in the B-horizon. Com (Zea mays)
and rye (Seale cereale) yields were greatly enhanced by the addition of sludge but
there was little difference in yield between the sludge loading rates. Uptakes of
heavy metals in the com and rye occurred in response to sludge application. Zinc
was the only metal that consistently appeared at levels above the control.
-31-
In 1985 Kau et al showed that soil with high iron oxide content, in conjunction
with soil liming, may give the best control of metal availability for accumulator
species. Such as Swiss chard when grown in soil amended with sludge. They also
found that increasing sludge application reduced soil pH, increased the amount of
Cd and Zn extractable by DTP A and decreased metal uptake by plants.
Heckman in 1987 showed that excessive applications of sewage sludge and
manure have led to the accumulation of heavy metals, in particular Pb, Cd, Cu,
and Zn, in many agriculture soils. The contamination of soil with these elements
can results in phytotoxic effect and the increased entry of toxic metals into the
food chain, along with in the deterioration of surface water and ground water
(Yingming and Corey, 1993). Furthermore, adverse effects on soil microbial
activity were found even at very low concentrations of heavy metals in soils
(McGrath et al 1995). However metals may become more available to plants with
time depending on the biological and chemical conditions in soils after
termination of sludge application. In particular, Cd and Zn are ,easily mobilized
by soil acidification. Zinc was found to reach phytotoxic concentration and Cd
and exceed food quality tolerance values in crop plants (Bidwell and Dowdy,
1987). Metal input into agricultural soils must be maintained at levels that
minimize adverse phytotoxicity and risk to consumers through the food chain.
Furthermore, the bioavailability and mobility of heavy metals in polluted soils
should be controlled, giving special attention to the effects pf soil pH and organic
matter content (Smith, 1994B).
Abdel-Sobber et al (1988) noticed that when Municipal and industrial waste
were applied to soil Cd significantly increased the Cd/Zn ratio in both crops
especially in Swiss chard and Cd and Zn ratio in plants (Zea maize and Swiss
chard) was affected by both Cd and Zn in soil.
When supplemented in a culture solution at a level above 28.1 J.lg/L, Cd was
found to decrease the concentration of~ Zn, and Mn in wheat biomass but did
not affect the absorption of Fe and Cu (Jalil et at al 1994). Zinc enhanced Cd
uptake by spring wheat grown in sand when applied at levels of 1.042 and 1.542
g/kg (Dudka et al.; 1994). Abdel-Sabour et al, (1988) found for com (Zea mays
-32-
L.) that Zn reduced Cd uptake, while Williams and David (1976) found that Zn
generally enhanced Cd plant uptake.
All experiments dealing with sewage sludge application to soil have not shown
positive results. The chemical properties of sludge make the positive or negative
results of its impacts on land. Negativity can overcome by submitting the
residues, like high heavy metals or phytoxic substances, excess labile organic
matter, pathogenic microorganisms etc, to a suitable composting process (Witter
and Lopez, 1988).
Kim et al in 1988 selected twelve food plants and grown them in greenhouse pots
to determine relative concentration of Cd and Zn in the plants grown in sludge
treated soils. They found that, in general, the cone. in the leaf tissue was the
highest and followed by root/tuber then followed by fruit/seeds/flowers come
last. The relative Cd and Zn cone. Of a food plant grown in sludge treated soils
were significantly differ·ent.
In a pot trails (Seeda et al; 1990) V faba was frown on sandy soil treated with
acid sludge (pH) to give a final concentration of 0-5% sludge in soil DM. they
noticed that electrical conductivity increased but pH and plant dry matter
yield/pot decreased with increasing percent of sludge. Plant tissue concentration
ofFe, Cu, Mn, Ni, Pb and Cd increased with sludge up to 3%. Uptake ofCu, Zn,
Mn and Pb increased with sludge up to 1.0% sludge and than decreased
Tadesses and Shuford in 1991 found that Zn accumulation is more in wheat
tissues when they grew wheat in sludge amended soil at low pH and high rate of
sludge.
Sauerbeck 1991 showed that while the uptake of Cd by six different crop plants
increased linearly with metal concentration in the soil at concentrations ofCd less
than 4 mg kg"1, the uptake of Cd by the plants was independent of Cd in the soil
was greater than 5 mg kg-1.
Andersoon and Simon (1991) reported increasing levels of Cd in plants with
increase in levels of P fertilization. Zinc is another interesting heavy metal
--33-
because of its relatively high abundance, its enhancement of Cd mobility, and its
high mobility in soil and plant system.
Gorlach and Gam bus (1991) studied the effect of liming, adding peat and
phosphorus fertilization on the uptake of heavy metals by plants. They reported
that liming reduced the uptake ofNi and Zn most; adding peat ofCd, Cu and Pb,
reduced uptake the most while the effect of phosphorus fertilization was the least
in nearly all cases.
Mench at el in 1993 conducted a study to see the effect highly metal polluted
sludge on Maize growth. They found that plant yield decreased remarkably in the
highly metal-loading soil should be attributed to 3 major factors: Mn deficiency
in leaves, and increase concentrations of Cd and Ni in plant especially Ni in
roots.
Heavy-metal polluted soils have for long beer. recognized as a serious problem in
industrialized part of Western Europe (Alloway 1993) and North America
(Hutchinson and Whitby 1997), and it has recently become apparent that the
problems in Eastern Europe and Russia are in many cases even more extensive
(Kozlov et al. 1993). In heavily polluted areas of this sort there are usually two
main forest damage zones (Tikkanen and Niemela 1995): an industrial barren
zone relatively close to the point emission source where the tree and ground
vegetation are completely destroyed, and an outer zone where the vegetation is
progressively suffering from serious damage but is capable of slow recovery if its
emissions are drastically reduced.
In field study Mohammad and Battikhi (1997) found that sewage sludge
increased the extractable micronutrient· and heavy metals in soil and barley plant
straw and grains also.
Smith (1994) found that sequence of metal concentration in the plant tissues from
sludge-amended soils was Zn> Cu>Ni>Cd>Pb for wheat grain and carrot roots,
and Zn>Cu>Cd>Ni>Pb for spinach leave. The concentrations of metals in wheat,
carrots and spinach grown on sludge-amended soils in this study clearly showed
that metal uptake is plant-species dependent. (Schaurer et al 1980~ Vigerust and
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~Of Literature
Selmer-Olsen 1986; Lubben and Sauerbeck 1991;). This implies that, for a given
level of metals in soils, spinach leaves accumulate far greater amounts of metals
than wheat grain and carrot roots. This is primary because of their very low soil
to-plant transfer rations compared to those of Cd, Ni, and Zn.
Lur et al (1995) investigated the uptake of Cd and Zn by cereal crops from soil
fertilized with sewage sludge. They found that yield of barley and oats increased.
Cd, Zn and P content of plants increased due to sludge addition. Sewage sludge
had more available Cd and Zn in compare to soil. Coefficient of accumulation of
C and Zn from sludge decreased in the order roots>shoots>grains.
Miller et al in 1995 studied the heavy metal in crops as affected by soil types and
sewage sludge rates. For this they carried out a lysimetric test with barley and
Swiss chard at different anaerobically digested sludge rates. In their study they
found that metal content in plants increased with increasing sludge loading. Tke
concentration of Cd, Zn, Cu, and Ni in barley (Hordeum vulgare L.) straw was
higher than in grain. But the cone. of all these metals in Swiss chard (Beta
vulgaris L.) were generally greater than those in barley, especially Cd and Zn
were exceptionally high.
In green house experiment conducted to evaluate the availability of metals from
sewage sludge and inorganic salts, and the effect of pH and soil type in yield
and metal uptake (Cd, Zn, Ni and Cu) by wheat, Tadesse et.al. (1995) found
that by both applications plant tissue concentration increased. However,
increased pH cause decrease in heavy metal concentration in plant tissues.
Tsadilas, et al (1995) studied the influence of sewage sludge applications on
some soil properties and on the growth of wheat and com plants were studied
with pot experiments. The results showed that sewage sludge application
significantly influenced pH, organic matter content, electrical conductivity and
available phosphorus. Soil pH increased and tended to hold steady near neutrality
while organic matter content, electrical conductivity and available phosphorus (P)
increased. For the heavy metals investigated only total copper (Cu) and Zinc
increased but were below the limits given by the EC. A significant increase was
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observed in the concentrations of Cd, Ni, Cu, and Zn extracted by DTP A while
iron and manganese (Mn) were reduced showing a strong relationship to soil pH.
Several soil-related factors, namely pH, organic mater, Mn and Fe oxides, and
clay content determine the chemical associations of heavy metals and their
availability to plants (Narwal and Singh 1998). Among these factors, pH has been
regarded as major variables regulating the metal mobility in soil (Heckman at al.
1987). The sorption and the precipitant of heavy metals are enhanced by
increasing soil pH (Kiekens 1984; Alloway and Jackson 1991). These processes
help to explain the decreased mobility normally found in soils with a basic pH.
There are several mechanisms, which may act concurrently, that could explain
the observation that the plant uptake of metals increases with the increasing soil
metal concentration until it reaches maximum and there after is independent of
the total concentration in the soil.
Firstly, in soils which have received inputs of metals as the results of applications
of sludge, there is evidence to suggest that chemistry of the sludge may be
important in controlling subsequent metal availability in the soil (Corey et al.
1987). This is because sewage sludges typically contain a high proportion of
organic and amorphous oxide components which have ·a high capacity for
specific sorption of metals (Hae-nam Hyun et al; 1998; Jing and Logan 1992;
Luo and Chrisite, 1998).
Secondly, precipitations reactions could limit metal solubility (Christensen and
Tjell, 1984; Mahler et al; 1978). Increases in the total metal concentrations in the
soil above a critical limit for metal precipitation would not lead to further
increases in metal concentrations in the soil solution, and therefore there would
be no further increase in absorption of metals by the plants roots.
Finally, McBride ( 1995) postulated that root avoidance of a surface contaminated
soil layer might be involved in reducing metal uptake by plants growing in sludge
amended soils in which, for the field studies that have been performed, typically
only the top 20 em have been heavily contaminated with metals. (Williams and
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David 1977) clearly demonstrated this effect on Cd uptake in pot studies with
subterranean clover.
Eleiwa et al (1996) studied the effect of two sewage sludge on the growth of faba
bean. They found that no of nodules/plant, plants height and leaf area increased
significantly with the application of both sludge up to 5%. Root and shoots dry
weight and N, P content of plants also increased with both sludge at lower
concentrations. Zn and Cu content of roots and shoots increased by increasing the
rate of sludge, while Fe, Mn, Ni and Cr contents of roots were slightly effected
and they remained unchanged in the shoots.
Hooda et al (1997) grow wheat and spinach and carrot in previously sewage
sludge amended soil found that plant availability of heavy metal differed widely
among the crop species. The accumulation of Cd, Ni and Zn in the plants showed
the greatest increase ·COmpafed to their background levels. The Cu and Pb
accumulation in the plants grown on sludge amended soils showed only small
increase compared to those grown on uncontaminated soils. Multiple regression
analysis of various soil properties showed that the surest way to control the
accumulation of metals in food plants is by controlling their concentrations in the
soils. Furthermore, soils with a non-acidic pH and a clayey texture tended to
achieve better rontrol of metal accumulation in food plants compared to those
with an acidic reaction and a coarse texture.
When Hamon et al (1999) grew Raphanus satives L. in a soil historically
amended with sewage sludge at different rates and examined concentrations of
Cd ·and Zn in the plants and in corresponding rhizosphere soil solution, metal
concentrations in the plant displayed a plateau response. However, concentrations
of total or free metals in the soil solution did not display a similar response,
therefore the pre-requisite for determining that metal uptake by plants was limited
by sludge chemistry was not met.
Begonia et al, 2000 grew wheat in a Cd contaminated soil and identified that
wheat as a potential phytoextraction species because of its high biomass yield
under elevated Cd levels and its ability to translocate high amounts of Cd into its
shoots.
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Sherif et al (200 1) found that potato yield was high when they grew it in sludge
amended soil. Increasing rates of· sludge increased concentration of trace
elements (Fe, Zn, and Mn), organic matter and P availability in sludge amended
soil but did not reach the critical level oftoxicity.
Wong et al in 2001evaluated the feasibility ofusing a domestic (Tai Po sludge)
and an industrial (Yuen Long sludge) sewage sludge produced in Hong Kong for
the growth of vegetable crops. The acidic loamy soil with or without lime
treatment was amended separately with each sludge at application rates of 0, 5,
10, 25 and 50% (v/v) for the growth of a common local vegetable crop, Brassica
chinensis. The plant available metal contents, as indicated by the DTP A
extraction, increased with an increase in sludge amendment, but decreased with
lime amendment at each sludge application rate due to the reduced metal
availability at a higher pH. Sludge amendment enhanced the dry weight yield of
B. chinensis and the increase was more obvious for the soil with lime treatment.
The industrial sludge caused a lower yield than that of the domestic sludge
amendment and a significant reduction in yield at high application rates of Yuen
Long sludge was also noted. Tissue heavy metal contents, except for Fe,
increased as the sludge amendment rate increased while plant grown in Yuen
Long sludge amended soil contained higher Cr and Zn contents at each sludge
application rate. Liming the soil reduced the heavy metal contents in the plant
tissues, except for Fe, which were all below the allowable levels for vegetable
crops.
An experiment was conducted by Moral et al (2002) to estimate the contribution
of sewage sludge application to the input and availability of Fe, Mn, Cu, and Zn
in amended soils. In order to study the dynamics of these essential elements, the
experimental design was based on the incubation of two calcareous soils having
different textures (sandy clay loam and clay loam) amended with composted and
non-composted sewage sludge. A significant increase in available Fe, Cu, Mn
and Zn was observed. The application of increasing rates of sewage sludge
slightly increased the available fraction. of the micronutrients studied. The
influence of soil texture was to increase the available fraction in the clay loamy
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soil compared to the sandy clay loamy soil. Availability of Fe, Cu, Mn and Zn
continued to increase throughout the incubation period.
Antoniadis and Alloway (2002) studied the movement of heavy metals down the
soil profile and found that risk is greater in case of heavy loading of mobile
metals in soils, such as Cd, Ni and Zn, where metals have applied ai iow sportive
capacity soil.
Kipling et al (2003) applied different doses of poultry litter & municipal solid
waste on 13 different soils. They found that poultry litter increased yield of
peanut from all 13 sites while municipal sludge increased yield in 1 soil.
Antoniadis and Alloway (2003) opted two sites to see the leachability of heavy
metals by. sludge application. The first site (SI) was field receiving heavy loads
sludge from a nearby wastewater treatment plant, and the second (S2) was a farm
applying normal sludge rates of8 t ha-1 i 1 of the same sludge. Soil samples were
also taken 'by a nearby untreated control site. In S 1 the movement of heavy metals
was significant even down to 80cm depth compared to the control. In S2 the
concentrations of lead (Pb) and Zinc and the organic mater content were higher
than the control down to 20cm, while nickel moved significantly down to 80cm.
Clucas et al in 2003 studied the ex1ent of metal (Cd, Cr, Cu, Ni, Pb, Zn) leaching
from soils treated with metal-spiked sewage sludge was examined using large
undisturbed soil Jysimeters. MetaJ leaching from the soils were monitored
continuously over a period of 3 years after sewage sludge application.
Application of the sludge resulted in decreased pH and increased concentrations
and total amounts of Cd, Ni, and Zn in drainage leachates from some of the soils,
but had little effect on, or decreased concentrations of, Cr, Cu, and Pb. In some
cases, Ni and Zn concentrations in drainage leachates exceeded drinking water
and/or environmental standard; the leaching of these metals would seem unlikely
to pose a major environmental threat.
Speir et al in 2003 conducted an experiment to see the heavy metals in soil, plants
and groundwater following high rate sewage sludge application to land. They
observed that soil, pH was by far the greatest determinant of metal solubility and
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that the metal source, whether sewage sludge or geochemical, had little influence.
Results from extractant that solubilise other metal phases, i.e., NaN03, EDT A
and HN03, are also presented and discussed.
Biilent (2004) in his two years study, conducted a greenhouse experiment to
compare the effects of repeated applications of sewage sludge, MSW compost
and manure on the heavy metal accumulation in the leaf and fruit of tomato and
total and bioavailable heavy metal accumulation in greenhouse soil. They found
that sewage sludge and MSW compost amendments significantly increased Zn,
Cu and Pb contents both in leaf and fruits of tomato. Plant tissue concentrations
of Cd and Cr were low and not detectable. Sewage sludge and MSW compost
increased both total and DTPA extractable concentrations of Zn, Cu, and Pb and
also total concentrations of Ni and Cd in the greenhouse soil. Cr content of soil
was not changed with the applications of sewage sludge and MSW compost.
Total and bioavailable metal contents of soil in sewage sludge and MSW
compost applications were higher in comparison with manure application.
Results suggest that the increase in soil metal loadings resulting from sewage
sludge and MSW compost amendments has affected bioavailable metals.
Chantachonet al in 2004 conducted a study to investigate the phytoextraction of
lead (Pb) by two species ofvetiver grass (1--'etiveria zizanioides and V nemoralis)
irrigated with an increasing level of Pb for 12 weeks. In a laboratory study, the
removal of lead from soil was correlated with lead accumulation by roots and
shoots of both species of vetiver grass. High concentration of lead resulted in
decrease of growth, total chlorophyll content and biomass of V. zizanioides,
while V. nemoralis died after one week of application. A simulated field
experiment was conducted to examine the efficiency of vetiver grass in removing
lead from contaminated soil. The vetiver grasses, V. zizanioides and V.
nemoralis, were grown in soil contaminated with Pb(N03)2 for 3 months. The
removal of lead from soil was correlated with lead accumulation by roots and
shoots of both grass species. The grass roots took up more lead than the shoots.
Henning et al in 2004 conducted a glasshouse experiment to characterize soil
plant interactions of the main sludge-borne heavy metals (Pb, Cd, Zn and Cu) in
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two sludge (low metal and high metal) to different soil types (clayey, loamy and
sandy) on maize seedlings. The low metal sludge treatment showed the highest
yield for maize seedlings when compared to controls. The amendment of sludge
to the soil did indicate higher heavy metal content. Except for Cd, heavy metal
values in the soils (at the beginning and end of experiment) exceeded guidelines
due to very high background values in the soiL They have not found any negative
effects ofheavy metal contamination in plant parts ofthe crops.
Ni, Sung and Yang in 2004 studied the effect of phosphorus application on Zn
accumulation inS. alfredi H. For this they gave five doses ofP like 0, 31, 62, 124
and 248mgP/kg of soil. They found that shoot dry weight was significantly
affected by P application (except the 248mgP/Kg treatment) than for no P
application. Highest biomass of shoot was found at 31 mgP/Kg treatment. Zn
concentration in shoots with 3 1 mgP/Kg treatment higher than for no P
application after that with increasing doses of P, Zn concentration was found to
decrease.
Wang et al (2004) conducted a study to evaluate the effects of different modifier
(lime, humic acid and acids) application rates on crop growth and metal
accumulation through rice and soybean plants, and the joint effect of Cd, Pb, Cu
and Zn on migration and accumulation in soil plant system and found that all four
metals with lime and humic acids raised the height of rice plants in comparison to
only heavy metals treatment. While the height of rice was found to be lowest with
heavy metals with acid treatments_ The height, dry weight of aboveground plant i•
parts, and yield of soybean were lower than the rice plants.
Adams et al in 2004 have done a study to investigate the relationship between
soil properties and the concentration of Cd in wheat (Triticum aestivum L.) and
barley (Hordeum vulgare L.) grain. For this they collected wheat and barley grain
samples from two long-term sewage sludge applied soil. Cadmium concentrations
were much lower in barley grain than in wheat grain under comparable soil
conditions. Multiple regression analysis showed that soil total Cd and pH were
the significant factors influencing grain Cd concentrations.
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A growth room experiment (Zheljazkov and Warman, 2004) was conducted to
evaluate the bioavailability of Cu, Mn, Zn, Ca, Fe, K, Mg, P, S, As, B, Cd, Co,
Cr, Hg, Mo, Na, Ni, Pb, and Se from a sandy loam soil amended with source
separated municipal solid waste (SSMSW) compost. Basil (Ocimum basilicum L.)
and Swiss chard (Beta vulgaris L.) were amended with 0, 20, 40, and 60%
SSMSW compost to soil (by volume) mixture. Basil plants in 20 or 40% compost
treatments reached flowering earlier than plants from other treatments. Additions
of SSMSW compost to soil altered basil essential oil, but basil oil was free of
metals. The results fi-om this study suggest that mature SSMSW compost with
concentrations of Cu, Pb, Mo, and Zn of 311, 223, 17, and 767 mg/kg,
respectively, could be used as a soil conditioner without phytotoxic effects on
agricultural crops and without increasing the no1mal range of Cu, Pb, and Zn in
crop tissue.
Solubility and fractionation of P and heavy metals (Zhang et al in 2004) were
evaluated in media containing 0, 25, 50, 75, or 100% compost derived from
biosolids and yard trimmings for potential impacts on the environment. As
compost proportion in peat-based media increased from 0 to I 00%,
concentrations of total P, Cd, Cu, Ni, Pb, Zn, and Mn in the media increased
whereas concentrations of total Co and Cr decreased. Except for Cu, all heavy
metals in the water-soluble fraction decreased with increasing compost proportion
in the media, because of higher Fe, AI, and Ca concentrations and pH values of
the composts than the peat. When the media pH is controlled and maintained at
normal range ofplant growth (5.5-6.5), leaching ofthe heavy metals is minimal.
However concentration of all forms of P were still higher in the media amended
with compost because of higher total P concentration in the compost.
Schlossberg et a\ in 2004 conducted a 2-yr field study and evaluated
environmental and technical parameters associated with CCB (coal combustion
by-products)-organic waste utilization as growth media in turf grass sod
production. In both years, sod biomass was greatest in media containing biosolids
and fly ash. Using CCB-organic waste mixes at the rates 200 to 400m3 ha-1 is a
rapid and environmentally safe method of Bermuda grass sod production.
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Simmons and Pongsakul in 2004 done a study on cadmium (Cd)-contaminated
soils, to predict Cd and zinc (Zn) uptake in crops as determined by readily
measurable "indicators" of Cd and Zn phytoavailability would be a useful
management tool to rapidly evaluate and prevent food chain Cd contamination
risk. For the soils and soybean bean tested, the results indicate that readily
exchangeable (0.01 M eaCh-extractable) and sorbed+ organically bound
(0.005 M DTPA-extractable) forms ofZn and Cd are dependent on soil pH
Karamanous et al in 2004 carried out a study to see whether near maximum
yields can be obtained with lower Cu rates. Two experiments were carried out in
1999 and 2000 to address these two issues, one with 4 rates of Cu (0, 1, 2, and
4 kg Cu ha·1) and one with 12 rates (0, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 kg
Cu ha·1) in the form ofCuS04·H20. A total of 16 trials were carried out with hard
red spring wheat on two groups of soils, namely, one containing soils that are
considered Cu deficient (~0.4 mg DTPA-Cu kg·1) and one sufficient (>0.4 mg
DTPA-Cu kg·'). There was a significant wheat seed yield increase to Cu
fertilization in deficient soils only with the application of up to 5 kg Cu ha·'. Near
maximum yields were obtained with application of 2 kg Cu ha·t, thus providing a
more economic alternative to prairie producers. Application of rates greater than
5 kg Cu ha·l led to a gradual yield reduction and at 10 kg Cu ha·• as CuS04·5H20,
the yield was actually lower than that of the control. Hence, over fertilization
with CuS04·5H20 results not only in an economic waste but a danger of toxicity.
When lime is added, solubility of aluminum decreases and the soil pH is raised.
Aluminum is soluble at pH values below 5.5 and toxic levels are frequently
encountered in Florida mineral soils with a pH of less than 5.0. Organic soils
contain little aluminum; therefore, plants can tolerate low pH levels on these soils
without adverse effects. Lime also affects the solubility of other elements;
therefore, some plant nutrients are made more available by liming while toxicities
caused by excessive concentrations of other nutrients are reduced. (Chambliss et
al, SS-AGR-46, edis.ifas.ufl.edu).
Liming soils offers a means of minimizing the risk of food chain contamination
by reducing the plant uptake of sludge-borne heavy, metals (Wiiliams et al 1987;
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Jackson and Alloway 1991; Smith 1994). Several studies, however, have
indicated that liming may not always have a significant effect, and that the
etTectiveness of liming could also vary depending on the soil, metal, pH value of
the limed soils and crop species (Hwmphill et al 1982; Peper et al 1983; Kuo et al
1985; Erikson 1989).
Tsadilas et al conducted a field experiment in a strongly acid Typic Haploxeralf
(pH 4.9) with winter wheat. They applied fly ash at two rates and also with
sewage sludge and found that fly ash and SS (sewage sludge) significantly
increased soil pH and in a lesser degree organic matter content. As a consequence
of soil pH improvement, grain yield was significantly increased especially in the
treatments including FA at the higher rate or FA plus SS. Total concentrations of
the metals studied were not significantly influenced (data not presented).
However, soil pH significantly affected -available "forms and some fractions of
the metals studied. ·-· Available" Ni and Zn concentrations were decreased in the
treatment with the highest FA rate. The same was true for exchangeable Ni Zinc
extracted by DTPA was positively correlated with organic matter content.
(http://www.eom.slu.se/icobte/additional/SP5orTsadilas.pdt)
(b) Literature related to India
Mishra et al (1995) investigated the effect of sewage sludge and Mussoorie rock
phosphate (MRP) on biomass production and uptake of heavy metals by spinach.
They found that sludge treated plants grew slightly more than control plants but
accumulated more Cd, Pb Cu and Cr than the control plants. Plants grew best in
presence of both sludge and MRP; these plants did not accumulate heavy metals
to the same extent as the sludge treated.
Srivastava et al (1995) have done an experiment to see the effect of ordnance
factory effiuent on seed germination and early growth performance of pea seeds
was studied. They found that the ordnance factory effiuent was highly deleterious
for the germination where early growth performance of seeds and as the
concentration of effiuent increases the deleterious effect also increases thereby
showing positive correlation.
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~Of Literature
Arora and Chauhan in 1996 conducted a study with the tannery effluents to see
the effect on seed germination percentage, seeding growth and total biomass in
some varieties of Hordeusn vulgare, Eflluents collected from Mahajan Tannery,
Agra caused a significant reduction in germination percentage, length and total
biomass in almost all the varieties.
When Rao and Shantram (1996) grew maize in soil amended with Urban Solid
Waste (USW) no visual deficiency or phytotoxic symptoms were evident. Fe
uptake by maize was decreased at all levels and that was due to low Fe content
of USW. They also reported that Zn uptake by maize increased by application
of USW compared to control. Heavy metal uptake by plant was also high in
their study.
Karpate and Choudhary (1997) carried out a study to of the effect of fly ash and
fly ash water was studied .on Triticum aestivum. Plants were either irrigated with
25%, 50%, 75% and 100% fly ash water or grown in 50%, 70%, 90% fly ash
amended soil. At lower concentrations the fly ash water and fly ash had
stimulatory effect on the crop. However, at higher concentrations the treatment
showed deleterious effect. Moreover, all concentrations of fly ash water and fly
ash were found to .have damaging effect on cytology and genetic material.
A study was carried out to (Dutta and Boissya, 1997) investigate the effect of
eflluent of the Nagaon Paper Mill (Hindu stan Paper Corporation Ltd.) on the
germination of rice (Oryza sativa L. var. Masuri) seed and subsequent growth of
seedlings. They found that effluents particulall y at higher concentrations inhibit
germination and growth of seedlings. Further, it was observed that rice seeds
collected from effiuent affected area are less viable and even the viable seeds
show delayed germination in comparison to the ones collected from control areas.
Prasanna et al (1997) were studied the effect of dairy efiluent on seed
germination, seedling growth and pigment contents of green gram (Phaseolus
au reus L.) and black gram (Phataseolus mungo L. ). A gradual decrease in the
germination of seeds, seedling growth and pigment contents with increase in
eflluent concentration was observed. The best germination, seedling growth and
pigment contents were observed in 25% effiuent concentration. Thus effiuent can
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9\eview 0( Literature
be used safely for irrigation purposes at proper dilution (25%) for beneficial
cultivation.
In Calcutta municipal solid waste application in field also increased the toxic
heavy metal concentration. It was found that heavy metal accumulate maximum
in root region than other (Olaniya et al., 1998).
Barman et al ( 1999) investigated heavy metal accumulation in fields receiving fly
ash from a thermal power plant and subsequent uptake in the different parts of the
crop plants growing in the respective field. The metal content (Cd, Cu, Zn, Fe,
Ni, and Pb) in the soil samples are higher than that in the control soil and lower
than that in the background value. In case of Cd, Zn and Pb the concentration is
either below or within the critical concentration. ln the edible parts of plant Cu,
Zn Pb the concentrations are within the recommended permissible limits, whereas
Cd Cr and Ni show a little higher concentration.
Solid waste is a scourge in all-Indian mega-cities. The quantity of solid wastes
generated in urban areas, ranges from 0.3 to 0.5 Kg/capita/day, depending upon
the lifestyle of the people (Ahsan 1999). In Delhi alone, more than 5000 tones of
municipal solid waste are generated every day. An integrated solid waste
management should include the following components; waste minimization,
material recovery and recycling, waste processing and energy recovery, waste
transformation and waste disposal.
Siddiqui et al in 2000 conducted an experiment to study the effect of fly ash on
growth and yield of mustard (Brassica juncea Czern and Coss). Study revealed
that application of lower concentrations (20 and 40%) of fly ash significantly
enhanced the growth and yield parameters. 40% level of fly ash proved to be
optimum for all the parameters studied. It can be concluded that soil amended
with 40% level of fly ash proved best in enhancing the yield of mustard and seeds
were safe for human consumption.
The effect of sewage biosolid composts as a nutrients source for the food and non
food crops was studied under green house condition with varying levels of
composts, namely 0, 22.7, 45.5 and 91.0 gm composts pot -1. The results showed
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that increasing levels of compost addition increased the yield of all the crops.
(Chitdeshwari, 2001 ).
Barman et al in 2001 studied the effects of industrial water of an electronic
component manufacturing unit with electroplating and its subsequent effects on
soil and plants receiving the effluent. The physico-mechanical parameters of the
soil samples were not changed, but the concentration of metals were
comparatively higher than the control soil. Higher accumulation of metals was
found in the plant parts in naturally growing weeds and cultivated crop plant
irrigated with treated effluent. Elevated accumulation of metals in Eichhornia
crassipes and Marsilea sp. growing along the effluents channel has been
identified as a potential source of biomonitoring of metals particularly for Cu and
Ca and can be utilized for the removal of heavy metal from wastewater.
It has been shown that germination rate, root shoot length dry matter yield
reduced by the application ofdectro plating effluent on the germination of maize
(Selvakumari et al, 2002).
Ramachandran and D'Souza (2002) carried out an experiment on the uptake of
Cd, Zn and Mn from soils amended with Cd enriched sewage sludge. They
noticed that the dry matter yields of both maize and mung bean shoots decreased
with increased Cd content of sewage sludge added to different soil types.
Khan and Bhardwaj (2002) did a green house experiment to evaluate the effect of
fly ash (FA) on the growth, development and metal ions uptake by board bean
(Viciafaba) and chilli (Capsicum .frutescens) plants. The results indicated that the
lower doses ofF A upto 15 gm Kg-1 soil had a beneficial effect with regards to
growth, development and nutrient uptake by both the plants grown in FA
amended soil. At higher doses beyond this dose posed a significant phytotoxic
effect with the increasing concentrations ofF A.
The accumulation of As, Cd, Cu, Hg, Ni, Pb and Zn in industrial solid waste
amended soil has been studied. The soil samples were taken at the depth of 15 em
from the surface. The concentration of some metals was found to be higher. The
• ·-47-
~mew Of Literature
detected concentration of metals has also been correlated with the organic matter
and chemical demand ofthe samples. (Pande and Shrivastava, 2002)
Ritesh & Sihorwala in (2003) studied the industrial waste from rolling and
picking industries and found that this waste is acidic, comes under hazardous
waste & also have leach ability of heavy metals like Ni, Cr, Co Fe & Cu in
sludge.
A sequential extraction procedure used to study the changes in the distribution
and mobility of Cd, Cr, Cu, Ni, Pb and Zn in an acid lateritie soil amended with
alkaline coal ash and neutral sludge individually and with their mixture of equal
proportions at 25, 50 and 75 mg/ha application rates and grow with peanuts. The
vegetative plant parts showed maximum accumulation of metals indicating a
physiological barrier in the transfer of metals from the root to the kernel. Linear
relationships of total concentrations of heavy metals in soil with that in the crop
were observed (Kumar et al 2003).
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top related